package demo3;

interface Usb{
    public void start();
    public void stop();
}

class UsbDiskWriter implements Usb {
    public void start() {
        System.out.println("开始访问U盘");
    }
    public void stop() {
        System.out.println("停止访问U盘");
    }
}

class Camera implements Usb {
    public void start() {
        System.out.println("开始使用相机");
    }
    public void stop() {
        System.out.println("停止使用相机");
    }
}

class Mobile implements Usb {
    public void start() {
        System.out.println("开始使用手机");
    }

    public void stop() {
        System.out.println("停止使用手机");
    }
}

public class Test {
    public static void main(String[] args) {
        UsbDiskWriter usbDiskWriter = new UsbDiskWriter();
        Camera camera = new Camera();
        Mobile mobile = new Mobile();
        usbDiskWriter.start();
        camera.start();
        mobile.start();
        usbDiskWriter.stop();
        camera.stop();
        mobile.stop();
    }
}










